msm: vidc: Video firmware supports only random mode

Kernel sets only random mode to simplify the intra refresh mode
setting for encoder. All other modes will be deprecated.

CRs-Fixed: 2384822
Change-Id: I0b509538d23e61cc0e691e9735d83434923d39f5
Signed-off-by: Karthikeyan Periasamy <kperiasa@codeaurora.org>